Former prime minister Imran Khan on Monday demanded a “proper inquiry” into the death of Sub-Inspector Aamir Shahzad Bhadar, the complainant and a “critical witness” of the Wazirabad assassination attempt on the PTI chairman.

Bhadar, who was the station house officer of Sadar police station in Wazirabad, died of cardiac arrest on Sunday. The officer was at his house in his native village Bhadar near Kharian town of Gujrat when his condition deteriorated, according to family sources.

He was driven to Kharian Combined Military Hospital where doctors pronounced him dead on arrival.

Bhadar was the complainant in the case registered against the Nov 2 gun attack on Imran. He had been working at the Sadar police station, where he was posted days before the attack occurred.

A PTI worker had died and 14 others, including the former prime minister and party leaders, were injured in the attack at Wazirabad’s Allah­wala Chowk, where the party’s “Haqeeqi Azadi” march against the federal government had stopped on its way to Islamabad.

In a series of tweets today, the PTI chairman called the death of officer “sudden”, saying that Bhadar was a “critical witness in unearthing the conspirators” behind the assassination plot being investigated by a joint investigation team (JIT).

He also reiterated claims that the JIT’s record was being tampered with.

“It is equally important to recall the mysterious circumstances surrounding the death of FIA investigator Dr Rizwan as well as the deaths of Maqsood Chaprassi and all other witnesses in Shehbaz Sharif’s money laundering case,” the ex-premier added.

After the attack, Imran had blamed Prime Minister Shehbaz Sharif, Interior Minister Rana Sanaullah and a high-ranking officer of the Inter-Services Intelli­gence for planning the incident and attempted to nominate them in the case.

Since then, several PTI leaders, including the chairman, have reiterated that the attack was a part of a “well-coordinated” plan executed by at least three shooters to eliminate Imran Khan.

A JIT, formed by the Punjab government, had reportedly concurred with Imran’s claims that the attack was carried out from three different shooting sites. The team, which has been reconstituted twice, was headed by Lahore CCPO Ghulam Mehmood Dogar.

But earlier in January, the government formed a new team to probe the attack, a move that was rejected by the PTI. According to the notification, the team was constituted under Section 19(1) of the Anti-Terrorism Act (ATA), 1997.